Developer John Laing Partnership is suing structural engineer SDP for £800,000 after wheelchair ramps it designed for a housing project in south London were found to be too steep and narrow
The designs, for the Ujima Housing Association and the South London Family Housing Association, caused the Penwith Manor Estate scheme in Lambeth, south London, to be delayed for more than eight months, according to a writ issued by Laing.

SDP refused to accept liability for the defects and Laing carried out remedial works and paid damages totalling £660,160. It is now SDP for the delay costs as well as interest running at £144.69 per day.

The writ says SDP's designs failed to comply with the housing associations' requirements. It says the engineer was negligent in failing to exercise the skill and care expected of reasonably competent professional.

In the writ, served by lawyer Merricks, Laing says the St Albans-based consultant made paths to three wheelchair properties too narrow, and failed to provide for level areas at the front of 98 properties.

Laing discovered the problems in June 1999; subcontractors had carried out the work without realising that there were problems with the designs.

SDP refused to accept liability so Laing agreed to carry out remedial works and pay damages for the delay

The writ said that the site should have been handed over to the housing associations in November 1999, but because of the delays, work was not completed until July 2000.

A spokesperson for Laing said: "The situation between John Laing Partnership and SDP has been ongoing for a number of years and we have endeavoured to reach a solution.

"Failing this, we have started legal proceedings and are awaiting a timetable from the courts."